Maths shows the nature of "tipping points" for climate and ecological crises

According to the most detailed study of its kind, humans must be careful not to cross the "point of no return" that leads to an ecological disaster such as the loss of tropical forests or irreversible climate change.

The thin line that separates the Earth's current climate from a frozen climate – what is known as the snowball state – has been explored in a new research led by the University. of Reading which combines mathematics with climate science.

The researchers analyzed how random events and human action could be combined to reach a tipping point, where a natural state goes from one very different state to another.

The results, published today in the journal Letters of physical examination, can be applied to the Earth's climate, landscape features or ecosystems, such as virgin forest, to help us understand how they can be altered or destroyed after reaching a point of no return.

Valerio Lucarini, professor of statistical mechanics at the University of Reading and lead author of the study, said: "Climate change or catastrophic declines in natural features such as forests all occur in the same way as a trip. in a mountainous region, like two valleys divided by a mountain pass which one must cross to move between them.

"Locating this boundary has allowed us to better understand when we are likely to see transitions in the natural world.This helps us to define a safe workspace, allowing us to adapt our behavior to stay in this position and realize when a transition could occur.Cutting trees, damaging ecosystems or altering the climate could cause us to move too close to a tipping point, thus risking dramatic and irreversible changes. "

The new research builds on a previous study (2017) published in Nonlinearity by the same authors, which used a dynamic method to identify the tipping point between two competing states. This study led to an unprecedented understanding of climate properties on global stability and was presented as one of the highlights of the year by the IOP Science magazine which published it.

The new study helps us better understand the critical points of Earth's climate. The Earth rocked repeatedly between a warm climate and a snowball about 650 million years ago, before the beginning of multicellular life.

The team used random fluctuations to simulate an approach at such a tipping point, showing how a transition from one state to another becomes likely.

This can be applied to natural features such as the Amazon rainforest. The tropical rainforest undergoes fluctuations due to fires, drought or deforestation caused by man, but is able to regenerate to a certain extent. The research could help us judge how a forest would become unable to absorb these events and begin an unstoppable decline, allowing us to act accordingly to preserve it.

The team is now planning to apply its results to a real climate transition that can be observed today, analyzing the processes that lead to the beginning and end of the monsoon season in some parts of the world. or to those who are responsible for different traffic patterns around the world. Atlantic Ocean.

Professor Lucarini said: "The crossing of a tipping point relies on a combination of random events that accumulate to produce the transition.

"Human action may be insignificant when the tipping point is far away, but it may be the last straw, and understanding this context is essential in judging when we could switch to a new state."